cooperating. about a third of the packages from china, shipped by the u.s. postal service, still do not have advance content information. >> cronin: the gordon jin drug traffickingn their own communications and advertisements online, say that they ship to five continents, in all 50 states. they advertised, and it seemed accurate, they had special ways to bypass customs in the u.s., the u.k., the e.u. and russia. >> pelley: assistant u.s. attorney matt cronin told us that gordon jin would often slip fentanyl past u.s. customs by shipping it to a co-conspirator in the united states, posing as a legitimate chemical company. shipments between chemical companies weren't considered suspicious. a large crate would arrive at the u.s. company, but inside, there would be as many as 50 individual drug packages, each addressed to the person who'd ordered them. >> cronin: so they take out these 50 different parcels and send it across the united states and, as i mentioned, even the world. >> pelley: they were going out to the door of the individual people that ordered them online. >> cronin: that's right. we realized that we found gordon jin's drug trafficking route, essentia